In May 2015, the Colombian government suspended fumigation after the WHO found that the Monsanto pesticide was “likely” to cause cancer.

Colombia's attorney general urged the government, after over a year of suspended use over health concerns, to resume aerial fumigation of coca crops, promoting the measure as the only effective way to prevent therm from resurfacing.

The seven-page report, signed by Attorney General Nestor Humberto Martinez and addressed to the Justice Ministry, sparked a national controversy, bringing into question the Colombian government's shift in drug policy last year, when it decided to suspend fumigation.

After over 14 years of aerial eradication of coca crops—a measure heavily influenced by the U.S.-led war on drugs—the government decided to include a health and human rights perspective in its drug policy.

In May 2015, shortly after the World Health Organization found that the pesticide used in aerial fumigation was “likely” to cause cancer, the government suspended the use of the chemical called glyphosate and sold by Monsanto.

In the document, Martinez insisted on the necessity of resuming aerial fumigation, arguing that the reemergence of illicit crops had doubled in the past four years, from almost 48,000 hectares in 2012 to almost 97,000 in 2015, a 39 percent increase over the past year, according to the United Nations Office on Drugs.

The country's Chief Prosecutor Alejandro Ordoñez backed the proposal, saying he had urged authorities not to suspend fumigation in 2015, expressing concerns over civilian safety.

However, both the health and justice ministries rejected the measure.

Justice Minister Jorge Londoño Ulloa told reporters that 2007 was the year with the largest amount of illicit coca crops, despite aerial fumigation carried out then.

He also highlighted that it would be juridically impossible to implement the measure again, given that Colombia's constitutional court backed the government's decision in an historic ruling..

Health Minister Alejandro Gaviria Uribe added in a communique that “in the case of fumigation over illicit crops, the civilian population cannot express whether it would be willing or not to expose itself to the risk, unlike fumigation over licit crops.”

Moreover, the suspension of aerial fumigation was a central point of the peace negotiations that recently concluded in Havana, Cuba between the Revolutionary Armed Forces of Colombia and the government. If the peace deal is signed and approved in the popular referendum, it would also bear legal consequences.

Critics of aerial fumigation argue that Monsanto's product is not only dangerous for health, contaminating sources of water and neighboring crops with the winds, but also useless to limit the expansion of coca crops in the long term. First, because coca crops are also mixed with legal crops; second, campesinos resort to various strategies to mitigate the harmful effects of the pesticide on the coca plant; third, coca crops can be transferred to other places quickly.

Meanwhile, the U.S. continues to apply pressure, being a strong supporter of aerial fumigation both for political and economic reasons, while the country's right-wing, opposed to the peace deal, also pushes for renewed fumigation.